Resin composition for nonaqueous electrolyte secondary battery, separator for nonaqueous electrolyte secondary battery using same, resin composition for electrode mixture layer, electrode for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery

Abstract

A resin composition for a non-aqueous electrolyte secondary battery that includes a vinylidene fluoride copolymer having a constituent unit derived from vinylidene fluoride and a constituent unit derived from a fluorine-containing alkyl vinyl compound. A melting point, measured in accordance with ASTM D3418, of the vinylidene fluoride copolymer is from 105° C. to 125° C., and a mass fraction Wa of the constituent unit derived from the fluorine-containing alkyl vinyl compound in the vinylidene fluoride copolymer, a degree of crystallinity DC of the vinylidene fluoride copolymer, and a degree of amorphicity DA of the vinylidene fluoride copolymer satisfy Equation (1) below:4.7≤Wa×(DC/DA)≤14  (1).

The invention claimed is: 
     
       1. A resin composition for a non-aqueous electrolyte secondary battery comprising:
 a vinylidene fluoride copolymer having a constituent unit derived from vinylidene fluoride and a constituent unit derived from a fluorine-containing alkyl vinyl compound, wherein 
 a melting point, measured in accordance with ASTM D3418, of the vinylidene fluoride copolymer is from 105° C. to 125° C., 
 a mass fraction W a  of the constituent unit derived from the fluorine-containing alkyl vinyl compound in the vinylidene fluoride copolymer is 18 mass % or greater and 30 mass % or less, and 
 the mass fraction W a  of the constituent unit derived from the fluorine-containing alkyl vinyl compound in the vinylidene fluoride copolymer, a degree of crystallinity D C  of the vinylidene fluoride copolymer, and a degree of amorphicity D A  of the vinylidene fluoride copolymer satisfy Equation (1):
   4.7≤ W   a ×( D   C   /D   A )≤14  (1).
 
 
 
     
     
       2. The resin composition for a non-aqueous electrolyte secondary battery according to  claim 1 ,
 wherein the fluorine-containing alkyl vinyl compound is hexafluoropropylene. 
 
     
     
       3. The resin composition for a non-aqueous electrolyte secondary battery according to  claim 1 , further comprising:
 a dispersion medium, 
 wherein the vinylidene fluoride copolymer having a primary particle size of from 10 to 700 nm is dispersed in the dispersion medium. 
 
     
     
       4. The resin composition for a non-aqueous electrolyte secondary battery according to  claim 1 ,
 wherein the resin composition is a powder having an average secondary particle size of from 30 μm to 200 μm. 
 
     
     
       5. A separator for a non-aqueous electrolyte secondary battery comprising:
 a separator film; and 
 a resin layer disposed on at least one surface of the separator film, 
 wherein the resin layer contains at least a solid content of the resin composition for a non-aqueous electrolyte secondary battery described in  claim 1 . 
 
     
     
       6. A resin composition for an electrode mixture layer comprising:
 the resin composition for a non-aqueous electrolyte secondary battery described in  claim 1 ; and 
 an electrode active material. 
 
     
     
       7. An electrode for a non-aqueous electrolyte secondary battery comprising:
 a current collector; and 
 an electrode mixture layer disposed on the current collector, 
 wherein the electrode mixture layer contains a solid content of the resin composition for an electrode mixture layer described in  claim 6 . 
 
     
     
       8. Anon-aqueous electrolyte secondary battery comprising:
 a pair of electrodes; and 
 a separator disposed the electrodes, 
 wherein the separator is the separator for a non-aqueous electrolyte secondary battery described in  claim 5 . 
 
     
     
       9. A non-aqueous electrolyte secondary battery comprising
 at least a pair of electrodes, 
 wherein at least one of the pair of electrodes is the electrode for a non-aqueous electrolyte secondary battery described in  claim 7 .